System for controlling knitting



y 7, 1940- w. DUBILIER 2,l99.396

' SYSTEM FOR CONTROLLIfi'G KNITTING Filed Sept. 27, 1934 I 3 Sheets-Sheet 1 ATTORNEY May 7, 1940. w. DUBILIER.

SYSTEM FOR CONTROLLING KNITTING Filed Sept. 27, 1934 3 Sheets-Sheet 2 INVENTOR WILLAM DUB/415R ATTORNEY May 7, 1940.

W. DUBILIER SYSTEM FOR CONTROLLING KNITTING Filed Sept. 27, 1934 3 Sheets-Sheet 3 INVENTOR WILL MM DUB IL/EE' ATTORNEY Patented May 7, 1940 UNITED STATES PATENT OFFICE 18 Claims.

My invention relates to novel apparatus for and methods of knitting and more particularly relates to novel apparatus for and methods of providing a mesh of uniform appearance for making silk apparel such as silk stockings.

The natural silk thread used in silk wearing apparel is produced by normally interlacing or rolling together the individual fine threads obtained from the silkworm. A predetermined in number of such fine threads are used, depending on the thickness of the final thread to be wound on spools. As the interlacing of the thin threads proceeds, it often happens that there is a variation in the number of individual threads used,

l resulting in a variation in the thickness of the final thread.

Such slight variations in the thickness of the threads, particularly if the. variations extend to any great length, becomes a serious defect inthe production of silk apparel of wide mesh, as in the case of sheer stockings. Here the mesh used is relatively wide, so that the silk threads are individually visible. Variations in the thickness of these threads thus become readily noticeable, destroying the much desired aesthetic efiect of uniformity in mesh and thickness.

I have discovered that I can detect such variations in the thickness of the thread and automatically compensate therefor to produce a uniform appearance in the mesh.

Accordingly, an object of my invention is to provide novel apparatus for and methods of detecting the variations in thickness of a silk thread. I

A further object of my invention is to provide novel apparatus for and methods of manufacturing silk wearing apparel of uniform appearance.

Still a further object of my invention is to provide novel apparatus for and methods of manufacturing silk sheer stockings of uniform appearance.

Another object of my invention is to provide novel apparatus for and methods of automatically compensating for variations of thickness of a thread.

.Still another object of my invention is to provide electrical means for measuring, detecting and compensating for variations in thickness of a silk thread.

vide'novel apparatus for and methods of varying a condenser capacity in accordance with the Still another object of my invention is to pro- Still a further object of my invention is to prostant.

vide novel apparatus for and methods of con trolling the light impinged on a photoelectric cell in accordance with the variations in the thickness of-a silk thread.

There are other objects of my invention which 5 together with the foregoing will appear in the detailed description which is to follow in connection with the drawings in which:

Figure 1 is a circuit diagram and perspective illustrating one embodiment of my invention for 10 measuring the thickness of a silk thread by controlling the light impinged on a photoelectric cell;

Figure 1a. is a cross section through a-a of Figure 1b;

Figure 1b is a detail of the adjusting mechanism of Figure 1;

Figure 2 is a circuit diagram showing a modified form of the invention disclosed in Figure 1;

Figure 3 is a circuit diagram of a modified 20 form of my invention in whichv a capacity of a condenser is varied in accordance with the thickness of a silk thread;

Figure 4 is a circuit diagram of a further modified form of the circuit shown in Figure 3;

Figures 5 and 6 indicate how the downward excursion of a sinker bar forms a loop in the thread; 1

Figures 7, 8 and 9 illustrate how the depth of horizontal excursion of the needles aflects the length of the loop in the thread; and

Figures 10 to 13 are enlarged cross-sectional views of the method of controlling the condenser capacity.

Referring now more specifically to Figure 1, I have shown, for purposes of illustration, a spool II on which, is wound a silkthread l2 whose possible variations in thickness are to be measured. The silk thread 12 is carried over the guiding rods l4 and between guiding plates l5, having a slot lli therein to permit light to pass through .there, as will be described hereinafter. The thread i 2 is then guided over traveling guide I! to the knitting machine.

' Opposite member IS, a source of light 2| throws abeam of light through the lens 22, focused at slot 16, past thread l2 and through the lens 23. This beam is then impinged on the photoelectric cell 24, the. amount of the light impinging on the photoelectric cell 24 at' any instant being, as is shown, a function of the thickness of the silk thread passing in front of the beam at that in- The photoelectric cell 24 of any wellknown construction is connected to a source of potential 25 through a series resistance .26. The

variations in the impinging light cause similar variations in the current flowing through the photoelectric cell 24 and the resistance 26. This varying current causes corresponding variations in the potential of point 26 which is connected directly to the grid of the tube 21 for amplification. I

For purposes of illustration I have shown two tubes, 21 and 28, directly coupled from anode to grid with suitable potentials applied to the electrodes through the resistances 29 and 30 by means of taps 3| and 32 with a source of B battery 33 connected across resistance 30, and a biasing battery 33 for the grid of tube 21. This arrangement is to provide further amplification of the potential variations corresponding to the light impinging on the photoelectric cell.

It will be understood that any other suitable amplifying circuit may be used for amplifying the potentials generated at the photoelectric cell. Moreover, although a photoelectric cell with an operating battery is disclosed, it will be understood that a voltaic type of cell generating its own energy may be substituted. Although I have disclosed a light arrangement in which the amount of light impinged on a photoelectric cell is varied in accordance with the thickness of a thread by varying the amount of light which passes the thread, I may, if desired, use the refleeting principle in which a beam of light is refiected from the thread, the amount of light thus reflected varying in accordance with the thickness of the thread.

As the amount of light impinging on the photoelectric cell changes with the variations in thickness of the thread, the voltage impressed across the input of the first tube varies correspondingly and the current flowing in the output circuit of the last tube is thus also varied. The output circuit of the last tube is connected by the conductor 34 through an electromagnet 35 which controls the plunger 36. Plunger 36 (biased by spring 31 to the right end of its travel when no current flows in the electromagnet 35) controls the adjustment (to be described) for varying the mesh in accordance with the thickness of the thread. It will be understood from the following description that a sufiicient time delay is allowed so that the portion of the thread which produced the electrical effect for operating magnet 35 has reached the machine.

The width of the mesh produced depends upon the lengths of the loops and these in turn depend upon the movement of the needles. This variation is obtained as follows:

The needle bar 38, with needle 39 in place for operation is movable vertically. This motion is imparted to it by lever 40 while the rocking or presser motion is caused by levers 4|, 42 and 43. Cam lever 43 is provided with roller 44, which works against presser cam 45. In the absence of any other means of regulation the outline of cam 45 would determine the length of the loops, as it keeps the needles 39 at a fixed distance from the well known sinkers. A number of levers (not shown) are ordinarily, however, distributed equally over the entire length of the machine, to limit the travel of lever 43 in the direction of the arrowhead. This is done by stud 46, which arrests the motion of the needle controlling levers in the manner illustrated, thus keeping roller 44 away from cam 45. It is clear-that any change in the position of stud 46 relative to lever 43 will also change the motion of this lever and thus the length of the loops. Such changes in the position fine adjustments in the length of the loops. By

means of hand lever 5| a screw 52 (Figure 1a) is turned which throws lever 53, and with it roller 54, towards or away from cam 55, as required.

The operation will now be quite obvious. As cam 55 rotates, roller 4.4 will follow and, depending on the setting of 52, the motion of the follower 44 will be imparted to regulating shaft 41, since the parts carrying screw 52 are secured to the shaft 41 by set screws as shown.

Rocking of shaft 41 in turn rocks lever 48 to move pins 46, which in turn controls/the extent to which follower 44 will be allowed to follow cam 45, and therefore the size of the loops. A plunger 56 working in ratchet teeth holds 41 in any desired position. Thus the length of the loops can be accurately adjusted to suit all requirements.

The operation of the device will now be obvious.

The silk thread is constantly being fed between the source of light and photoelectric cell to the knitting machine. As the thickness of the thread varies, the light passing around the thread and impinged on the photoelectric cell varies correspondingly and in turn varies the voltage impressed on the input of the first tube. As the output from the last tube is thus varied, electromagnet 35 is variably operated and through proper mechanical connections, controls the excursion of the needles and therefore the mesh.

When the thickness of the thread becomesv less, a closer mesh is desired. A thinner thread permits a greater amount of light to be impinged on the photocell. More current then flows through photocell 24 and resistance 26. The potential of point 26 is proportionately increased, making the grid oftube 21 more positive which thus causes an increased output current flow through resistance 29. The corresponding drop in potential at point 29' is transmitted as a decreasing potential to the grid of tube 28. This increases the anode to cathode resistance of tube 28, resulting in a smaller current, flow in its output circuit. A decreased current fiow through electromagnet 35 causes it to correspondingly decrease its attractive force on the plunger 36. When normal output current is flowing through electromagnet 35,

it is designed to attract the plunger 36 to the center of its operating position. This is the normal position corresponding to the normal thickness of thread. A thinner than normal thread thus causes a decrease in the current output which results in spring 31 pushing plunger 36 towards the left. This action causes the excursion of needle bar 38 to become less as herein described.

It will be obvious that other forms of amplifying circuit may be used or, if desired, I may modulate a local modulator for increasing the detecting action of the silk thread thickness. It will be further obvious that the mechanism herein disclosed is schematic and merely for the purpose of illustrating one application of my invention.

In Figure 2 I have disclosed a modified form of my invention in which the mesh is controlled not only by the thickness of the thread, but by the length of thread over which this variation in thickness persists. I have discovered that when the variation in thickness exists for only a short length of the thread that this does not noticeably afiect the appearance of the knitted article andthat variations in thickness become apparent only when the length of the thread over which the variation in thickness occurs extends for a predetermined length. Accordingly the control of the mesh should be eiiected only if the variation in thickness of the thread occurs for that predetermined length. Such acontrol is disclosed in Figure 2.

In this figure I have disclosed a modified form of my invention in which the spool ll. carries the silk thread I2 which is guided over the roll 59 between guide plates 55 having a slot 56 therein and thence over the guide plates 57, slotted at 59 similarly to plates 55, to the knitting machine. Sources of light BI and 62 operating through their lens systems 63 and 64 impinge light on their respective photoelectric cells 65 and 66, the intensity of the light impinged varying in accordance with the thickness of the silk passing by the slots 56 and 59 and obstructing the beam of light.

The photoelectric cells are each connectedacross the common potential supply 58 through their respective equal series resistances 61 and 68. Variations in the light intensity impinging on these cells cause corresponding variations in the potentials of points 61' and 68, this action being identical to that of point 26' in Figure 1.

A special electron tube 18, having two independent control grids, is used. These grids are directly connected to the points 61' and 68' as indicated in Figure 2. Battery 58 is for properly and equally biasing these grids with respect to the common cathode. Interposed between the anode of the tube 10 and the B potential source 58 is a relay 69 which controls plunger 'H. Arm 72, attached to the end of this plunger, projects between the contacts 68 and 60'.

When very little current flows through relay 69 the plunger H is held against contact 68' by spring 13. Normal anode circuit current flowing through relay 69 corresponds to the condition when a normal thickness of thread passes through the machine. The relay is designed to attract plunger H just enough to positiomthe arm 12 centrally between contacts 60 and 68' when normal current flows. This position of the arm 12 is indicated in Figure 2.

When the light impinging on one photoelectric cell increases, more current flows through the corresponding resistances 61 or 68, raising the potential of point 61' or '68. The increase in potential of the connected grid tends to decrease the anode to cathode or internal resistance of the tube 18, just as in the case of Figure 1. However, since the potential of the other grid has not been changed, there results a much smaller internal resistance decrease than would occur if this other grid were absent.

When the light impinging on both photoelectric cells increases by a like amount, both grids increase in potential equally. The effect now is similar to that in a single grid tube or triode, namely, that a normal decrease in the internal resistance occurs. The converse readilyfollows. The operation of tube 10 is thus seen to be most responsive to equal variations impressed upon both its grids.

When the light impinged on one photocell varies from the predetermined amount, the variable effect on the electron tube 10 is not sumcient to operate the relay 69 in the output circuit. When, however, the variation in thickness persists over the distance L between two sources of light and through corresponding slits, then the two photocells simultaneously afiect the electron tube 10 to produce variations in the. output current flow. The relay 69 will be operated to in turn operate its armature H to cause arm 12 to engage contact 60 or 68'. g

If a thinner thread persists over the length L, it will pass more light to each of the photoelectric cells, raising the potentials of the grids of tube 19 and increasing the current flow through relay 69. When this increase equals a predetermined amount, arm l2 is attracted until it contacts point 80. The circuit of battery 75 and electromagnet 35 is then completed through lead 14. Cam 38 is released to the left to raise crank 46 to produce a closer mesh as explained in connection with Figure 1. When the thread is no longer thin, contact 60 is broken and electromagnet 36 attracts cam 38 to its normal position.

Conversely, when a thicker than normal thread persists over length L, a predetermined decrease of the currentthrough relay 69 permits its spring 13 to cause arm E2 to contact point 68. The circuit of electromagnet T1 and battery 15 is then completed through lead l6. When electromagnet 11 is thus energized, it attracts its plunger 18 against the pressure of spring '79 to cause the lever to bring the tension plates BI and tension plates- 8| and 82 is transmitted as a tension to the thread l2 passing between them. This tension will stretch the thicker thread back to normal thickness;

Thus .it will be seen that in accordance with this feature of my invention, small variations in the thickness of the thread do not aifect my apparatus, but when the variations extend for a distance suflicient to affect the appearance when the thread is woven into a stocking or the like, that is to say, when the length ofthe variation is sufiicient to make it visible within a reasonable distance, my apparatus automatically functions to compensate therefor by varying the weave or the actual thread thickness.

In the above I have disclosed and described an electro-optical system for controlling a relay through an electrical current in accordance with variations in the thickness of the thread.

In an alternative method for carrying out my invention, I-provide means for producing electrostatic variations in a con enser in accordance with the variation in thickness of a thread, the electrostatic variation in turn effecting an electrical circuit. As shown in Figure 4, the spool H carries a threadl2 which is guided over roll 83 and between the platesof a condenser 85. The condenser 85 is connected across the terminals of a grid condenser 86 connected to the grid of tube 81. Tube 81, whic is here shown as a three-electrode tube, is p ovided with a grid leak resistance 88, connected across a grid andcathode of the tube. A variable condenser and inductance 89 and 9| form a tuned circuit which is part of a regenerative circuit. Tube 81' is coupled, preferably directly, to the amplifier tube 92 and thepower for the system is supplied through the potentiometer 93 connected across 'the terminals of a. suitably source of energy at 90.

4 used. Connected in the output circuit of the sec ond tube 92 is a relay 94, controlling armature 95.

A second condenser 96 is connected like the first condenser 85 across the terminals of grid condenser 91 which in turn is connected to the connected in series and jointly control an energizing circuit for the relay I0'I. When a predetermined thickness of the thread passes the condenser 85, the capacity of the condenser is such that it impresses a predetermined voltage across the input of tube 81 and a predetermined current flows in the output circuit of tube 92.

For the normal thickness of thread, circuit adjustments are made such that the current flow is insufiicient to operate the relay winding 94 connected in its circuit. When a variation in the thickness of the thread occurs, this will vary the capacity of condenser 85 is a manner well understood by those skilled in the art; and inasmuch as the condenser 05 is connected in parallel with condenser 86, the effect will be to vary the rectifying action of the grid capacities to produce a corresponding variation in the direct current output of the tube. This will reveal itself in the form of an increased current fiow in the output circuit of tube 92 to an amount sufiicient to energize the relay 94 which will thereupon operate its armature to its closed position. have no effect at this time. If, however, the

variation in the thickness of the thread con-- tinues sufficiently long so that the dielectric in the second condenser 96 is varied, that is to say,

the variation of thickness occurs over the distance L so that the capacities of the condensers 85 and 96 are simultaneously varied, a variation in the output current of tube I02 will be produced, as described in detail in connection with the first circuit, from a current value insuflicient to energize relay I09 to a current sufficient to energize relay I04.

Armatures 95 and I05 will thus be simultaneously operated to closed position to in turn complete an energizing circuit for the winding of relay I0'I. Relay I0'I upon energization by battery I06 will operate its armature I08 to complete an obvious energizing circuit I09 for the electromagnet 35 which, through suitable mechanical connections, controls the excursion of the sinker bars 20 and thus the width of the mesh. When the thickness again returns to its normal value, the above described operations are reversed and the sinker bars are restored to their normal position. The slope or shape of the upper rods 38' of cam 38 may be designed for a change in width of mesh corresponding to the predetermined change in the thickness of the thread.

In a further modified form of my invention shown in Figure 3, an oscillator circuit, consisting of the electron tubes I2I and I22 and a feedback circuit, including the inductance I23 extending from the output of tube I22 and in inductive relation with the inductance I24 of the tuned circuit, including the variable condenser I25, is arranged to oscillateat a predetermined frequency in the manner described in detail in This will ber 1,990,216.

As described in that application, the direct coupled amplifier is operated from a potentiometer comprising the resistances I26, I21 and I28 connected across a source of power, the anodes of the tubes being in substantially multiple relation with each other. The condenser 85, whose capacity is varied in accordance with the thickness of the thread in the manner described in connection with condenser 85 of Figure 4,15 connected across the terminals of a resistance I3I and in the output circuit of tube I2I. In this circuit connection the variations in capacity of the condenser 85-do not affect the frequency of the oscillations generated by the oscillators since the cell is so placed that it does not afiect the constants of the oscillator circuit. With this arrangement, however, a modulation of the oscillator is obtained in accordance with the oscillations of the capacity of the condenser 85, and these modulated signals fiow in the output circuit of the second tube I22 and through the winding of relay I32, controlling the armature As in the case of Figure 4, a similar circuit is provided, including the electron tubes I34 and I35 directly coupled and connected to the oscillator circuit I36 through the inductance I31, connected in the output circuit of tube I35. Condenser 96, connected across the terminals of resistance I38, controls the amplitude of the oscillatory signals flowing in the output circuit of tube I35 and through the winding of relay I4I to control the armature I42. Armatures I33 and I42 are connected in series so that when these armatures are operated by their energized windings, they moveto close their respective contacts and complete an energizing circuit I45 through the winding I43 which by its armature I44 controls the energizing circuit I45 to the electromagnet 35 which, as described in connection with other figures, controls the excursion of sinkers 20 for controlling the width of the mesh.

Normally the amplitude of a current flowing in the output circuit of the second tube of each of the oscillators is such, as a result of the capacity of condensers 85 and 96 respectively, that relays I32 and MI are not energized.

As described in the co-pending Ash application referred to hereinbeiore, a change in capacity of these condensers would produce a considerable increase in the amplitude of the oscillating current suficient to energize the relay in the output circuit. If the change in capacity occurs in both condensers 85 and 96, due to the fact that the variation in the thickness of the thread persists for the length L, then the variation in the output current of both oscillators will be sufiicient to energize their corresponding relays I32 and MI and the energizing circuit will be completed for the relay I43 which in turn will energize electromagnet 35 for controlling the width of the mesh.

In the above I have described arrangements in which the weaving machine is affected in accordance with variations in the thickness of the silk thread. I have discovered that I can similarly eliminate streaks due to variations in thickness of the thread in stockings by varying a tension on the thread. This variation in tension results in a corresponding variation in the thickness of the thread.

In Figure 2 I have illustrated one simple arrangement for' carrying this out by utilizing tension plates 8| and 82.

In Figure 3 I use the same arrangement exthe thickness of the thread or of the width of the mesh is merely illustrative, and any number of variations in the principles involved may be devised.

In Figures 10 to 13 I have illustrated various arrangements of condensers that I may use for measuring the capacity of the thread. Thus in Figures 10 and 11 two straight plates are shown with the diameter of the thread considerably magnified to illustrate the dielectricv effect. In Figures 12 and 13 I have illustrated condensers in the form of arcs and arranged to permit the thread to pass therebetween. suitable constructions of condensers may be used in carrying out my invention.

It will be understood that I have disclosed a number of diiferent circuits, including straight amplifying circuits or oscillators controlled optically through photoelectric cells or by electrostatic variations of a capacity, but that these illustrations are merely by way of an example, the principle of my invention, namely the control of an electrical circuit in accordance with the variation in the thickness of a thread to in turn compensate therefor in the knitting machine, may be carried out with other types of electrical circuits than that herein disclosed, as will now be obvious to those skilled in the art. Other means than optical or electrostatic may be used for measuring the thickness of the thread and affecting an electrical circuit thereby.

The control by these circuits may be applied to any type of practical knitting or weaving machine as the particular type of machine used is not part of this invention. It would be a simple task for any person skilled in the art to. link the plunger 36 of electromagnet 35 to the loop or weave control lever of any such machine, including a circular knitting machine.

For illustrative purposes I have merely schematically indicated a simple arrangement for determining the width of the mesh in a knitting machine by controlling the excursion of the sinker bars. As I have above stated, actuating the proper control lever of any similar mechanism with my circuits would be just as efiective.

In an actual machine, I may design for a suitable time lag between the detection of the variation in the threadlhickness, and the corresponding operation of the mesh' width control mechanism.

It will be obvious from the above that my invention may take many different forms than those above illustrated, and I do not intend to be limited except as set forth in the appended claims.

I Claim: I a

1. The method of maintaining a substantially uniform appearance of a silk stocking which comprises automatically varying the mesh in accordance with the variations in thickness of the threads making up the mesh. a

2. The method of operating a knitting machine which comprises automatically varying an electrical circuit in accordance with the variation of the thread being applied to the knitting machine and controlling the operation of the sinkers in accordance with the variations of the electrical circuit.

Similarly, other 3. The method of operating a knitting machine which comprises automatically varying the sinkers thereof in accordance with the variations in the thickness of the thread being fed to the machine. 5

4. The method of operating a knitting machine which comprises automaticaly varying the sinkers thereof in accordance with the variations plates of an electrical condenser to vary its capacity in accordance with the thickness of the thread, controlling an electrical circuit in accordance with the variation in capacity to generate an electrical current, and controlling the excursion of the sinkers in accordance with the electrical currents generated.

6. The method of operating a silk stocking knitting machine which comprises passing the silk thread being fed to the machine between a source of light and a photoelectric cell to generate a variable electron stream in accordance with the thickness of the thread, controlling an electrical circuit in accordance with the variation in electron stream to generate a variable electrical current and controlling the excursion of the sinkers in accordance with the electrical currents generated.

'7. In a knitting machine, the combination with yarn feeding and knitting instrumentalities for forming a series of succeeding courses of similarly formed loops of normally uniform size, of a device for measuring variations in the amount of light admitted through a fixed aperture past the feeding yarn, means for varying the size of the loops formed from said feeding yarn, and means controlled by said measuring device for actuating said loop varying means to form larger loops from portions of said feeding yarn admitting a relatively small amount of light, and to form smaller loops from portions of said feeding yarn admitting a relatively large amount of light through said aperture.

8. In combination, a fabric forming machine, means for feeding yarn to said machine, and means including a detector responsive to waves radiated by said yarn for controlling the operation of said means.

9. In combination, a fabric forming machine, means for feeding yarn to said machine, said yarn being composed of lengths of varying characteristics, and means responsive to said characteristics for controlling the operation of said means.

10. In combination, a knitting machine, means for feeding yarn to said machine, and means including a detector responsive to waves radiated by said yarn for varying the operation of said means.

11. In combination, a knitting machine, means for feeding yarn to said machine, a photoelectric cell responsive to light radiated by the yarn, and means controlled by said cell for varying the operation of said means.

12. In combination, a knitting machine, means for feeding yarn to said machine, said yarn being composed of lengths of varying characteristics, and means at a point between the yarn supply and the needles of the machine and responsive to said means.

13. In combination, a fabric forming machine, means for feeding yarn to said machine, said yarn having lengths of different dielectric quality, means for varying the operation of the yarn feeding means, and a capacitance of which said yarn forms part for controlling said last mentioned means.

14. In combination, a knitting machine, means for feeding yarn to said machine at a predetermined rate, said yarn having lengths of diiferent dielectric quality, means for varying the operation of the yarn feeding means, a pair of condenser plates between which said yarn passes, and a tuned circuit comprising an electronic discharge device controlled by said condenser plates controlling saidmeans for varying.

15. In combination, a knitting machine, means for feeding yarn to said-machine at a predetermined rate, said yarn having lengths of difierent dielectric quality, means for varying the operation of the yarn feeding means, and a pair of condenser plates between which said yarn passes for controlling said means for varying.

16. In combination, a knitting machine, means said characteristics for varying the operation of for feeding yarn to said machine at a predetermined rate, said yarn having lengths of different dielectric quality, means for varying the operation of the yarn feeding means, and a capacitance of which said yarn forms part for controlling said means for varying.

17. In combination, a knitting machine comprising means for feeding yarn thereto, means controlled by the machine for varying in a predetermined manner the length of yarn fed to the machine during each course, means responsive to characteristics of successive lengths of said yarn, and means controlled by said last mentioned means for regulating the operation of said means for feeding.

18. In combination, a knitting machine, means responsive to characteristics of successive lengths of the yarn, means for feeding yarn to said machine past said means, means for varying the length of the yarn between said means responsive and said knitting machine, means controlled by said first mentioned means for controlling the feeding of yarn to said machine, and means controlled by said machine for actuating said means for varying the length.

' WILLIAM DUBIIJER. 

